High frequency switching circuit

Abstract

A single-ended switching circuit is constituted by a primary winding of a transformer, a switching circuit connected between the primary winding and a DC power supply and on-off operated with a predetermined cycle and also with a predetermined "on" period and a resonance capacitor connected in parallel with the primary winding. A magnetic amplifier, a rectifying element and a choke coil are connected in series between a secondary side circuit of the transformer and the load. The magnetic amplifier includes a saturable reactor which is held saturated during a half cycle of the voltage induced in a secondary winding of the transformer and remains unsaturated during the other half cycle of the voltage.

What we claim is: 
     
       1. A single-ended high frequency switching circuit arrangement, comprising: a switching element having a first terminal adapted to be coupled to a first terminal of a DC power source and a second terminal;   means for ON/OFF operating said switching element with a predetermined cycle and with a predetermined conductive period;   a transformer having a primary winding including a first end coupled to said second terminal of said switching element and a second end adapted to be coupled to a second terminal of said DC power source;   a resonance capacitor coupled in parallel with said primary winding;   magnetic amplifier switching means coupled to the secondary winding of said transformer and held conductive during a half cycle of the voltage induced in said secondary winding and nonconductive during the other half cycle of said voltage;   rectifying means for rectifying an output of said switching means;   a choke coil connected between the output terminal of said rectifying means and a load;   a filtering capacitor connected in parallel with said load; and   unidirectional means connected to said choke coil, load and filtering capacitor such as to form a closed circuit with said choke coil, load and filtering capacitor,   wherein said magnetic amplifier includes a saturable reactor connected between one end of said secondary side circuit and said rectifying means, a series circuit connected between the other end of said secondary side circuit and an output terminal of said saturable reactor and formed of a variable resistor and a unidirectional circuit element.   
     
     
       2. A single-ended high frequency switching circuit arrangement, comprising: a switching element having a first terminal adapted to be coupled to a first terminal of a DC power source and a second terminal;   means for ON-OFF operating said switching element with a predetermined cycle and with a predetermined conductive period;   a transformer having a primary winding having a first end coupled to said second terminal of said switching element and a second end adapted to be coupled to a second terminal of said DC power source;   a resonance capacitor coupled in parallel with said primary winding;   magnetic amplifier switching means coupled to the secondary winding of said transformer and held conductive during a half cycle of the voltage induced in said secondary winding and nonconductive during the other half cycle of said voltage;   rectifying means for rectifying an output of said switching means;   a choke coil connected between the output terminal of said rectifying means and a load;   a filtering capacitor connected in parallel with said load; and   unidirectional means connected to said choke coil, load and filtering capacitor such as to form a closed circuit with said choke coil, load and filtering capacitor,   wherein said switching means is a switching transistor connected between said secondary winding and said rectifying means.   
     
     
       3. A single-ended high frequency switching circuit arrangement according to claim 1 or 2 further comprising a coil connected between one end of said secondary winding of said switching means. 
     
     
       4. A single-ended high frequency switching circuit arrangement according to claim 1 or 2 wherein said switching element comprises a switching transistor said circuit arrangement further comprising a damper diode connected between a collector and an emitter of said switching transistor. 
     
     
       5. A single-ended high frequency switching circuit comprising: a transformer circuit including a primary winding and a secondary side circuit having a secondary winding;   switching circuit means including first switching means connected between said primary winding and a DC power supply and on-off operated with a predetermined cycle and a predetermined conductive period, and second switching means connected in series with said first switching means and held conductive during a half cycle of a voltage induced in said secondary winding and nonconductive during the other half cycle of said voltage;   resonance circuit means connected in parallel with said primary winding via said second switching means and including a coil and a resonance capacitor;   rectifying means for rectifying the output of said secondary side circuit;   a choke coil connected between the output terminal of said rectifying means and a load;   a filtering capacitor connected in parallel with said load; and   unidirectional means forming a closed circuit with said choke coil, load and filtering capacitor for passing inertial current through said choke coil.   
     
     
       6. A switching circuit power supply comprising: a switching element having a first terminal adapted to be coupled to a first terminal of a DC power source and a second terminal;   means for ON/OFF operaing said switching element with predetermined frequency and conductive periods;   a transformer having primary and secondary windings, the primary winding being coupled between said second terminal of said switching element and a second terminal of said DC power source;   a resonance capacitor coupled in parallel with said primary winding;   a magnetic amplifier coupled to said secondary winding;   means for rectifying an output from said magnetic amplifier; and   means for filtering an output from said rectifying means and supplying a filtered power signal to a load.   
     
     
       7. A power supply according to claim 6 wherein said magnetic amplifier comprises: a saturable reactor coupled to a first side of said secondary winding;   a reflux diode coupled to said saturable reactor; and   a potentiometer coupling said reflux diode to a second side of said secondary winding, output power of said power supply being controllable by varying the resistance of said potentiometer, the resistance of said potentiometer controll the power delivered by said power supply.   
     
     
       8. A power supply according to claim 6 wherein said filtering means comprises: a diode in parallel with an output of said rectifying means;   an inductor in series with said rectifying means; and   a capacitor coupling said diode and inductor.   
     
     
       9. A switching circuit power supply according to claim 8 wherein said switching element is a switching transistor. 
     
     
       10. A power supply according to claim 6 further comprising a coil coupling said secondary winding to said saturable reactor. 
     
     
       11. A switching circuit power supply comprising: a first switching element having a first terminal adapted to be coupled to a first terminal of a DC power source and a second terminal;   means for ON/OFF operating said first switching element with predetermined frequency and conductive periods;   a resonance capacitor coupling said second terminal of said first switching element to a second terminal of said DC power source;   a transformer having primary and secondary windings, the primary winding coupling said second terminal of said first switching element to said second terminal of said DC power source;   a second switching element having a first terminal coupled to a first side of said secondary winding and a second terminal;   a rectifier coupled to said second terminal of said second switching element; and   means for filtering an output from said rectifier and supplying a filtered power signal to a load.   
     
     
       12. A power supply according to claim 11 wherein said first switching element is a switching transistor. 
     
     
       13. A power supply according to claim 11 wherein said second switching element is a switching transistor. 
     
     
       14. A power supply according to claim 12 wherein said second switching element is a switching transistor. 
     
     
       15. A power supply according to claim 11 further comprising a coil coupling said secondary winding to said second switching element. 
     
     
       16. A switching circuit power supply comprising: a first switching element having a first terminal adapted to be coupled to a first terminal of a DC power source and a second terminal;   means for ON/OFF operating said first switching element with predetermined frequency and conductive periods;   a resonance capacitor coupling said second terminal of said first switching element to a second terminal of said DC power source;   a first inductor in parallel with said resonance capacitor;   a second switching element having a first terminal coupled to said second terminal of said first switching element and having a second terminal;   a transformer having primary and secondary windings, said primary winding coupling said second terminal of said second switching element to said second terminal of said DC power source;   rectifying means coupled to said secondary winding; and   means for filtering an output from said rectifier and supplying a filtered power signal to a load.   
     
     
       17. A power supply according to claim 16 wherein said first and second switching elements are switching transistors. 
     
     
       18. A power supply according to claim 17 further comprising a diode coupled in parallel with said first switching transistor. 
     
     
       19. A power supply according to claim 16 further comprising a second inductor coupling said secondary winding to said rectifier. 
     
     
       20. A power supply according to claim 16 wherein said filtering means comprises a filtering inductor in series with said rectifier and a filtering capacitor coupling said filtering inductor to said secondary winding.